The present invention relates to a latching valve. It finds particular application in conjunction with dual piloting valves and will be described with particular reference thereto. It will be appreciated, however, that the invention is also amenable to other applications.
Some control systems for air-operated devices utilize solenoid valves that are turned on (to supply a fluid such as compressed air) and off (to exhaust the fluid such as compressed air) by electronic and/or pneumatic control switches. A “normally closed” solenoid valve remains in a closed state until an activation signal (e.g., an electronic activation signal) is received by the solenoid valve (e.g., when the solenoid valve is energized). The “normally closed” solenoid valve transitions to an open state for only as long as the activation signal is applied to the solenoid valve (e.g., as long as the solenoid valve is energized). The normally closed solenoid valve returns to the closed state when the activation signal is no longer received by the solenoid valve (e.g., when the solenoid valve is de-energized). A “normally open” solenoid valve remains in a open state until an activation signal is received by the solenoid valve (e.g., when the solenoid valve is energized). The “normally open” solenoid valve transitions to a closed state for only as long as the activation signal is applied to the solenoid valve (e.g., as long as the solenoid valve is energized). The normally open solenoid valve returns to the open state when the activation signal is no longer received by the solenoid valve (e.g., when the solenoid valve is de-energized). A latching solenoid valve remains in either the closed state or the open state until an activation signal is received (e.g., until the latching solenoid valve is energized). The latching solenoid valve switches to the other state (e.g., switches from the closed state to the open state, or vice-versa) when the activation signal is received (e.g., until the latching solenoid valve is energized), and remains in the other state until the next activation signal is received (e.g., until the latching solenoid valve is de-energized and then energized again).
Current solenoid valves use fluid (e.g., compressed air) exiting a delivery port of the solenoid valve (e.g., when the solenoid valve is in the open state) for operating air-operated devices. The flow of air through the solenoid valve is determined as a function of diameters of the respective ports (or sealing seats). In some cases, the flow of air through the solenoid valve is restricted by ports with relatively smaller diameters. Simply choosing a solenoid valve having ports with relatively larger diameters is not always practical (e.g., the overall size of the solenoid valve itself may be too large for the available space and/or cost more).
The present invention provides a new and improved apparatus and method which addresses the above-referenced problems.